Stoker



March 21, 1939. F. H," BROWN 2,150,908

sToKER Filed 0G12. 22, 1934 Patented Mar. 21, 1939 UNITED STATES STOKER Francis H. Brown,

pany, Philadelphia, Pennsylvania Ridley Park, Pa., The Real Estate-Land Title and assignor to Trust Com- Pa., a corporation of Application October 22, 1934, Serial No. 749,437

13 Claims.

This invention relates generally to fuel conveying and distributing apparatus for installation in furnace structures whereby to provide for the supply of fuel for combustion therein, and this application is a continuation in part of my application Serial No. 608,228, led December 21, 1922 now Patent No. 1,977,620.

The principal objects and advantages of the present invention reside in the provision of an improved means for supplying solid fuel to a furnace lire box wherein the fuel is of a nely divided character, such for example as powdered coal, powdered coke, and the like, wherein the structure for delivering the fuel to the furnace serves as a distributing means as well as a grate structure; the provision of an improved grate structure wherein a solid fuel in a nely divided form may be introduced directly into the re bed and distributed evenly throughout the same for combustion purposes; the provision of an improved grate structure for delivering a nely divided solid fuel to a furnace wherein the grate structure serves to convey the fuel to the re box and as well distributes the fuel evenly while at the same time preventing clogging or caking of the fuel Within the delivery means; the

improved grate bar structure in which the grate bar structure is self-cleaning, and also in one of its forms serves to break up clinkers or other obstructions which may form due to poor combustion or due to the poor quality of fuel; and the provision of an improved grate bar structure which-may be conveniently installed in existing furnace fire boxes and which may be connected to a regulable source of supply which can be manipulated by an operator to maintain a substantially even fire within the fire box.

The foregoing, and such other objects and advantages as may appear as this description proceeds, are attained in structural embodiments of the invention as shown in the accompanying drawing, in which Figure 1 is a fragmentary plan view partially in section of a furnace structure showing an assembly of the grate bars arranged for delivery of powdered fuel to the re box thereof the grate bars being schematically represented in part.

Figure 2 is a schematic sectional view of a pair of the grate bar elements.

Figure 3 is a fragmentary sectional View of the grate structure of a modified form of the invene tion.

Figures 4 and 5 are, respectively, sectional and fragmentary elevational views of one of the grate bars.

Figure 6 is a fragmentary sectional view taken along the line indicated by 6-6 on Figure 1.

Referring now more particularly to the drawing, I have illustrated one form of furnace structure incorporating improvements of my invention, Figure 1 showing a fire box I 0 having side walls II and I2 and end walls not shown, which dene the areal of the re.

Within the fire box I I provide a plurality of cylindrical, hollow, rotatable grate bars I which are arranged with their respective perimeters closely adjacent to each other and all substantially in the same plane, as will be seen from an inspection of Figure 2.

The grate bars are of a perforated nature, as will be described more particularly hereinafter, and are mounted for rotation in suitable bearings IIa. and I2a at their respective ends.

At one end of each grate bar the grate bar itself ts into the bearing I Ia while at the opposite end each grate bar is xedly mounted upon a shaft 21 which fits into the bearings I 2a and passes through the wall I2. The outer ends of the shafts 21 are provided with worm gears I 6 which are in meshing engagement with a driving worm I'I which in turn can be driven by any convenient source of power.

At the ends of the grate bars adjacent to the bearings I Ia, means are provided, as will be hereafter fully described, whereby fuel is introduced into the grate bars from the fuel inlet branches I 8. These branches are in communication with a header I 9 which receives powdered fuel from a suitable source of supply under pressure. In each of the branches I8, there may be provided a damper 20 which may be vertically adjustable for controlling a relative amount of powdered fuel admitted to each of the grate bars. r

Inasmuch as the dampers 20 are outside of the furnace wall II, they may be adjusted and maintained in the desired position by any convenient means. For example, as shown in Figure 6, one convenient means consists of a threaded bar 33 terminating at its lower end in a forked portion 34 and attached t0 the damper 20 by a pin 35. The upper end of the bar 33 passes Vthrough 36 and 31 in the spaced brackets 38 and 39 fastened to the wall of the furnace, and is engaged by a hand wheel 40, placed between the brackets, which is threaded to receive the bar 33 and provided with annular bearing portions 4I and 42 which respectively bear against the lower surface ofthe bracket 38 and the upper surface of the bracket 39.

Thus an operator may regulate the quantity of fuel to be admitted throughout the furnace, thereby making uniform the fire throughout the fire box.. I

Referring now more particularly to the structure of the grate shown in Figure l, it will be observed from Figure 2 that the grate bars I5 are substantially cylindrical and are provided with a plurality of radial perforations 2l throughout the full length of the exposed portion of the grate bars, to form a surface as shown in Figure 5, and which preferably take the form shown in detail in Figure 4. The perforations 2| are ofthe general tapering form-from the interior of the grate bar toward the outer cylindrical surface thereof,

but are terminated short of the outer surface as indicated at 22, and then countersunk as indi-l cated at 23Vto form. a circumferential series of edge portions 24, which are exposed in the form of the invention shown in Figure 1 to the interior space of the nre box. Y Y

As these grate bars are rotated and the finely divided solid fuel is ejected therefrom, the fuel is consumed in the furnace. Should any vclinkers form and drop upon the grate bar these clinkers come in contact with the edge portions 24, and are either broken up or are reduced to such size as to either fall between the respective grate bars or become consumed in the fire'. Y

Inside of each of the grate bars I provide a cylindrical member 2 5 which 'fits the internal surface Vof the grate bar and extends from the grate bar at one end to abut and communicate with theV inlet I8 thus affording a conduit for carrying the powdered fuel' into 4the grate bar. This member 25 is retained in a stationary position by any convenient', means acting upon the end which extends from the grate bar `so that `the rgrate bar l5 rotates 'about the Vmember 25. The

upper sector of that portion of the member v2,5 which Vis Within the grate bar I5 is cutaway to form a longitudinal slot '26, as best shown in Figures 2 and 4. Thus, when the grate barrl5 is rotated about the member 25 the openings 2l of the grate bar are successively presented to the opening 26 and the powdered fuel under pressure is ejected through the openings of the grate bar. In view of the 'constricted form. of the openings, approaching the shape of a Venturi tube, a sprayingweffect is given 4tothe fuel as it is ejected from said openings, thus distributing the same in a cloud within the furnace fire box-so that itis readily consumed therein. l

The shaft 21 extends axially within thel grate bar, as shown in Figure 4, and this shaft may be provided with a series of triangular enlargements 28` which are 'adapted to rotate with the shaft within the trough 25, thus cooperating with the trough to remove any fuel which may become caked or packed therein. Thus the fuel is constantly ejected from'within the grate bar and does not become clogged, and thereby any blocking of the trough member due to the caking of the fuel is effectual'ly eliminated.

In the alternative form of the invention shown in V:Figure 3, the general voperative structureV is similar to that shown in Figures l, 2 and 4, but inasmuch as the furnacebed may for some purposes be provided with a fire brick bottom, the grate bars |5a, as shown in Figure v3, are mounted within protective cylindrical casing's 29, which are, provided with apertures v30 registering with complemental apertures 3l in the fire brick sections 32.

The forms of the invention shown in Figures 1, 2 and 3 are similar in that the fuel is allowed to escape in a cloud from the grate bars themselves, which serve asV conductors for the fuel from the header to desired points within the furnace structure. In the form of the invention shown in Figure 2, where the grate bar is exposed to the interior of the nre box, the trough is provided f'or controlling the discharge of the fuel through the apertures 2|. Similarly to the control by the trough25, the shields 29 shown in Figure 3 serve to controlV the point of dis'- charge of the powdered fuel into the furnace.

The elements 28 shown in Figure 4, may likewise be provided in the grate bar shown in Figure lIi as indicated so that in both of the forms of the invention shown, clogging of the grate bar due to caking of the fuel supply is effectually prevented.v v Y Y Having thus described my invention and illustrated its use, what I claim as new and desire to lsecure by Letters Patent is:

l. In a furnace, inrcombinatiom a fire box, and

means for injecting comminuted fuel in suspension into said fire box at a plurality of separate points, said injecting means including a plurality of distributing units each comprising two substantially cylindrical concentric tubes, one of said tubes being mounted for rotation relative to the other, and means for continuously rotating said rotatable tubes, said tubes having apertures which periodically register when said rotatable tube is rotated.

2. In a furnace, in combination, a fire box and a grate structure comprising a plurality of units which support and are overlaid by blocks ofrefractory material having perforations therein, said units each comprising a cylindrical casing having an aperture which registers with the apertures in said refractory blocks, and a cylindrical member having a plurality of radial perforations and rotatably mounted within said casing, means for introducing fuel in suspension into the fire box through said 'cylindrical members and means for continuously rotating said cylindrical members whereby the fuel is continuously agitated and the perforations in said cylindrical members periodically register with the apertures in said casings and refractory blocks.

8. In a furnace in combination with a firebox of a grate structure including a hollow cylindrical member mounted for rotation having a plurality of apertures therethrough, means for rotating said member, means for supplying finely divided solid fuel to the interior of said member for transmission through said apertures for com.- bustion, stationary means cooperating with the inside surface of said member f'or regulating the active area of said member, and means for preventing clogging of fuel within said member.

4. In a furnace in combination with a firebox, aV grate structure comprising a plurality of hollow cylindrical grate members having a plurality of apertures in the walls thereof and mounted for rotation and in parallel relationship adjacent each other, means for feeding finely divided solid fuel to the interior of each grate member for transmission through said apertures, means for controlling the direction of the passage of the fuel through said apertures, means for controlling the quantity of fuel passing through each grate and means for rotating' said grate members simeans for supporting said grate bars in parallel adjacent relationship, grate bars, a refractory wall disposed over said delivering nely divided rior of each grate bar,

solid fuel into the intemeans for restricting the of fuel within each grate bar.

7. In a furnace in combination with a firebox, a plurality of hollow cylindrical grate bars, each grate bar having a plurality of Venturi apertures therethrough, means for mounting said grate bars for rotation and in close parallel relationship, means for rotating said grate bars, means for delivering finely divided solid fuel to the interior of each grate bar for transmission through said apertures and means on each grate bar for controlling the active area of the grate bar.

8. In a furnace in combination with a rebox, a plurality of hollow cylindrical grate bars having a substantial wall thickness, each grate bar having a plurality of Venturi apertures therethrough, the number of said apertures and said wall thickness being so related that the outer grate surface 1s composed means for mounting said grate bars in close parallel relationship, means for revolving said grate bars simultaneously and in the same direction during combustion, means for delivering nely divided solid fuel to the interior of said split members stationary, whereby an active grate surface is continuously presented at the top of each grate bar.

9. In a furnace in combination with a fire box, a grate structure comprising a plurality of hollow cylindrical grate bars mounted for rotation and disposed in parallel relation, each grate bar combustion, means for controlling the direction of the ow of said fuel through said apertures and means for rotating said grate bars.

10. In a furnace structure, in combination, a grate structure including a rotatable hollow cylindrical grate bar having a plurality of peripheral apertures, means for delivering solid fuel in iinely divided form` to the interior of said grate and forcing said fuel out through said apertures, means associated with said grate bar for controlling the iiow of the fuel through said apertures, and means for rotating said grate bar.

11. In a furnace structure, in combination, a grate structure including a rotatable hollow cylindrical grate bar having a plurality of peripheral apertures, means for finely divided form to the tures, means for rotating said grate bar, and means within the grate bars for preventing the clogging of the fuel therein.

12. In a furnace structure, in combination, a grate structure comprising a plurality of hollow cylindrical grate bars mounted for rotation and disposed in parallel relationship adjacent to each other, each grate bar having a plurality of apertures, means for delivering solid fuel in nely divided form to the interior of each grate bar and discharging said fuel through said apertures for combustion, means for controlling the supply of fuel to each grate bar, means for controlling the'direction of discharge of the fuel through said apertures, and means for rotating said grate bars during combustion.

tures in the rotate.

FRANCIS H. BROWN. 

